阅读说明：本技术 一种诱发两相流的微通道实验系统 (Micro-channel experiment system for inducing two-phase flow ) 是由 张国渊 王杰 王豪 黎旭康 梁茂檀 王烈文 于 2021-09-06 设计创作，主要内容包括：本发明属于气液两相流实验技术领域,特别是一种诱发两相流的微通道实验系统,其特征是：至少包括：高压储液罐(8)、磁力齿轮泵(9)、流量阀(10)、微孔过滤芯(26)、流量计(27)、微通道实验单元(28)、冷凝单元(29)、回路辅助设备(30)以及数据采集单元(32)；所述的高压储液罐(8)、磁力齿轮泵(9)、流量阀(10)、微孔过滤芯(26)、流量计(27)、微通道实验单元(28)、冷凝单元(29)串联连接成回路,微通道实验单元(28)连接有回路辅助设备(30)以及数据采集单元(32)。它以便实现诱发包含沸腾和闪蒸两相流在内的两种不同类型的两相流现象,同时还可以根据不同的实验要求通过配置的不同参数实验装置零件,诱发两相流现象的工况和结构参数范围。(The invention belongs to the technical field of gas-liquid two-phase flow experiments, in particular to a micro-channel experiment system for inducing two-phase flow, which is characterized in that: at least comprises the following steps: the device comprises a high-pressure liquid storage tank (8), a magnetic gear pump (9), a flow valve (10), a microporous filter element (26), a flowmeter (27), a microchannel experiment unit (28), a condensation unit (29), loop auxiliary equipment (30) and a data acquisition unit (32); high pressure liquid storage pot (8), magnetic gear pump (9), flow valve (10), microporous filter core (26), flowmeter (27), microchannel experiment unit (28), condensing unit (29) series connection connect into the return circuit, microchannel experiment unit (28) are connected with return circuit auxiliary assembly (30) and data acquisition unit (32). The device can induce two different types of two-phase flow phenomena including boiling and flash two-phase flow, and can induce the working condition and the structural parameter range of the two-phase flow phenomena through configured experimental device parts with different parameters according to different experimental requirements.)

1. A micro-channel experimental system for inducing two-phase flow is characterized in that: at least comprises the following steps: the device comprises a high-pressure liquid storage tank (8), a magnetic gear pump (9), a flow valve (10), a microporous filter element (26), a flowmeter (27), a microchannel experiment unit (28), a condensation unit (29), loop auxiliary equipment (30) and a data acquisition unit (32); the high-pressure liquid storage tank (8), the magnetic gear pump (9), the flow valve (10), the microporous filter element (26), the flowmeter (27), the micro-channel experiment unit (28) and the condensation unit (29) are connected in series to form a loop, the micro-channel experiment unit (28) is connected with loop auxiliary equipment (30) and a data acquisition unit (32), wherein the high-pressure liquid storage tank (8) is a closed container capable of bearing certain high pressure and is used for containing experiment working media; the top of the high-pressure liquid storage tank (8) is provided with a pressure measuring and controlling device and an exhaust valve; a transparent glass tube water level gauge is arranged on one side of the tank body;

the magnetic gear pump (9) drives the working medium in the experimental loop to flow; the flow meter (27) is used for accurately measuring the flow rate of the fluid in the loop;

the flow valve (10) is a valve for controlling the on-off of the whole loop;

the diameter of the micropores in the microporous filter core (26) is 4-10 μm, so that solid impurities in a loop can be prevented from entering an experimental device;

the micro-channel experiment unit (28) is the body of the invention;

the condensing unit (29) is composed of a plate heat exchanger and a low-temperature cold water bath tank, and the condensing unit (29) is used for cooling the fluid working medium flowing out of the micro-channel experimental section to reduce the temperature of the fluid working medium to an original temperature value in the liquid storage tank;

the circuit auxiliary device (30) comprises at least: the high-speed camera is arranged right above the micro-channel experimental device and can shoot and observe the flowing boiling condition in the micro-channel, the flow pattern change of fluid and the flash boiling in the buffer cavity (14) in the experimental device through the transparent glass cover plate (4), and the LED light source is arranged beside the high-speed camera to irradiate the experimental device, so that the picture shot by the high-speed camera is clearer; the data acquisition part mainly comprises a data acquisition instrument and a computer, and the mainly acquired data comprise the temperature and pressure of 3 measuring points in the experimental device, the flow data in the magnetic flowmeter and the image data shot in a high-speed camera erected above the experimental device.

2. A two-phase flow inducing microchannel experimental system according to claim 1, wherein: the experimental working medium in the high-pressure liquid storage tank (8) is deionized water or ethanol liquid, a heater in the liquid storage tank is started in advance before an experiment to carry out advanced heating boiling treatment on the experimental working medium in the liquid storage tank so as to remove non-condensable gas in the fluid working medium in the whole experimental loop, and the whole experiment is started after the temperature of the fluid working medium in the liquid storage tank is reduced to normal temperature after boiling degassing.

3. A two-phase flow inducing microchannel experimental system according to claim 1, wherein: fluid working media in the loop flow through the microporous filter element (26) and the flowmeter (27) under the drive of the magnetic gear pump (9) and then enter the micro-channel experimental unit (28), boiling and flash evaporation two-phase flow is induced in the micro-channel experimental unit (28) and then flows out, and then the fluid working media flow through the condensing unit (29), are cooled by heat dissipation of the plate heat exchanger and finally flow back to the high-pressure liquid storage tank (8).

4. A two-phase flow inducing microchannel experimental system according to claim 1, wherein: the microchannel experimental unit (28) at least comprises: the device comprises a base outer plate (1), a micro-channel inner plate (2), an L-shaped cover plate (3) and an auxiliary component; the auxiliary component includes clear glass apron (4), goes up sealed apron (5), preheats ceramic electric heating plate (6), main heating ceramic electric heating plate (7), base planking (1) is the rectangle cuboid that has the cavity in, wholly adopts the material that heat conductivility is good, and it has rectangle microchannel entry (11) to distribute in proper order to the other end from rectangle cuboid one end, planking microchannel entry (19), planking microchannel (12), cavity (13), cushion chamber (14), circular channel export (15), includes three temperature pressure survey hole in rectangle cuboid one side, and three temperature pressure survey hole is respectively: a first temperature and pressure measuring hole (16), a second temperature and pressure measuring hole (17) and a third temperature and pressure measuring hole (18), wherein the first temperature and pressure measuring hole (16) is close to the rectangular microchannel inlet (11) but forms a vertical structure with the microchannel inlet (11), and the second temperature and pressure measuring hole (17) and the outer plate microchannel (12) are communicated with the connecting part of the cavity (13); the third temperature and pressure measuring hole (18) is close to the buffer cavity (14) and communicated with the buffer cavity (14).

5. A two-phase flow inducing microchannel experimental system according to claim 4, wherein: the microchannel inlets (11) are working medium inlet channels of the whole experimental device, are distributed on the side surface of the outer plate of the base at equal intervals, are in thin rectangles, and the number N is 6; the micro-channel inlet (11) is externally connected in the experimental loop and used as an inlet channel of the device to convey the experimental working medium into the micro-channel experimental device;

the outer plate microchannel (12) is of a 6 channel groove structure which is arranged at equal intervals, the cross section of the outer plate microchannel is in a thin rectangle shape which is the same as that of the microchannel inlet (11), and the outer plate microchannel is positioned on the upper surface of the outer plate (1) of the base; the width of the outer plate microchannel (12) is 10mm, the depth is 4mm, the outer plate microchannel is communicated with the microchannel inlet (11) and the cavity (13), and the fluid working medium is conveyed to the cavity (13) from the microchannel inlet (11);

the outer plate micro-channel inlet (19) is a structure formed by connecting a micro-channel inlet (11) and an outer plate micro-channel (12) and is a structure formed by six rectangular inlets which are arranged at equal intervals, the cross section size of the outer plate micro-channel inlet is the same as that of the micro-channel inlet (11), and working medium flows into the outer plate micro-channel (12) through the structure.

6. A two-phase flow inducing microchannel experimental system according to claim 4, wherein: the cavity (13) is a cuboid cavity with an opening on the upper surface and is positioned in the center of the base outer plate (1), and the upper surface of the cavity is flush with the upper surface of the base outer plate (1);

the buffer cavity (14) is a cuboid cavity with an opening on the upper surface and is a partial cavity reserved between the outlet (15) of the round channel of the experimental device and the cavity (13), the upper surface of the buffer cavity (14) is still flush with the upper surface of the outer plate (1) of the base, but the depth and the length of the buffer cavity are smaller than those of the cavity (13), step section mutation is formed at the joint of the cavity (13) and the buffer cavity (14), and the buffer cavity (14) can be used as an external environment lower than the saturated vapor pressure of the flowing medium in the channel to provide a space for the flash evaporation and boiling of the flowing medium in the device;

the circular channel outlet (15) is an outlet of a fluid working medium in the whole device, and the cross section of the circular channel outlet is circular; the first temperature pressure measuring hole (16), the second temperature pressure measuring hole (17) and the third temperature pressure measuring hole (18) are measuring holes with the diameter of 6mm, are distributed on the side of the micro-channel experimental device and are used as pressure and temperature measuring points; a temperature sensor and a pressure sensor are arranged in the measuring hole of the device for measuring the pressure and the temperature of the fluid working medium in the experimental device respectively; wherein the first temperature and pressure measuring hole (16) is close to the inlet (11) of the micro-channel and is communicated with the channel on the side of the device to measure the inlet temperature and pressure of the working medium in the device; the second temperature and pressure measuring hole (17) is positioned at the tail end of the outer plate microchannel, is connected with the microchannel on the side of the device, and is used for measuring the temperature and the pressure of the working medium which is about to leave the outer plate microchannel (12); the third temperature and pressure measuring hole (18) is close to the outlet (15) of the circular channel of the device, is communicated with the cavity (13), and measures the pressure and the temperature of the working medium flowing out of the micro-channel and entering the cavity (13); the pressure sensor and the temperature sensor are arranged in a first temperature and pressure measuring hole (16), a second temperature and pressure measuring hole (17) and a third temperature and pressure measuring hole (18), and the measuring holes provided with the sensors are sealed by sealant;

the micro-channel inner plate (2) is of a cuboid structure, the whole body is made of copper alloy materials with good heat transfer performance, the size (length multiplied by width multiplied by height) of the micro-channel inner plate (2) is the same as that (length multiplied by width multiplied by height) of the cavity (13), the micro-channel inner plate (2) and the cavity (13) are in interference fit during actual installation, the micro-channel inner plate (2) is fixed in the cavity (13), and the upper surface of the micro-channel inner plate is flush with the upper surface of the cavity (13); n microchannel grooves (20) are distributed on the upper surface of the microchannel inner plate (2) at equal intervals, the number n of the microchannel grooves (20) is usually the same as the number of the microchannel grooves (12) of the outer plate, and n belongs to {2,3,4,5,6 }, and the number can be adjusted according to actual experiments; the thin rectangular microchannel groove (21) is communicated with the outer plate microchannel groove (12), and the working medium flows into the microchannel groove of the inner plate after flowing through the outer plate microchannel groove (12).

7. A two-phase flow inducing microchannel experimental system according to claim 6, wherein: the microchannel groove (20) adopts a thin rectangular microchannel groove (21) structure, or an arc microchannel groove (22) or a step section channel groove (23) or a spray pipe microchannel groove (24) or a thin rectangular double-channel groove (25).

8. A two-phase flow inducing microchannel experimental system according to claim 4, wherein: the preheating ceramic electric heating plate (6) is positioned right below the outer plate micro-channel (12) and close to an inlet (19) of the outer plate micro-channel, and is used as a heat source of a preheating part to heat and pretreat liquid working media entering the device; the main heating ceramic electric heating sheet (7) is positioned right below the micro-channel inner plate (2) and used as a main heating part of the experimental device to heat working media flowing into the micro-channel of the inner plate (2) so as to induce the liquid working media in the micro-channel of the inner plate (2) to generate a boiling two-phase flow phenomenon; wherein the preheating ceramic electric heating plate (6) and the main heating ceramic electric heating plate (7) are externally connected with a direct current power supply to respectively adjust different heating powers; wherein, the ceramic electric heating sheets (6) for preheating and the ceramic electric heating sheets (7) for main heating are separated by a distance of 30mm-40mm to prevent the two ceramic electric heating sheets from having larger mutual interference when working at the same time.

9. A two-phase flow inducing microchannel experimental system according to claim 4, wherein: one side of the L-shaped cover plate (3) is provided with a zigzag micro isolation plate (31) which can partially shield the inlet (19) of the outer plate micro-channel so as to change the working medium pressure entering the outer plate micro-channel (12) and the thin rectangular micro-channel groove (21) and perform gradient adjustment to the working medium pressure in the micro-channel to a certain degree; working medium flows into the outer plate microchannel (12) from the outer plate microchannel inlet (19) and then flows into the thin rectangular microchannel groove (21) through the outer plate microchannel (12), wherein the preheating ceramic electric heating plate (6) is positioned at the lower position of the outer plate microchannel (12) and serves as a preheating heat source in an experiment, and the preheating treatment is carried out on the working medium when the working medium enters the microchannel device and does not flow into the thin rectangular microchannel groove (21).

10. A two-phase flow inducing microchannel experimental system according to claim 7, wherein: the inner plate of the thin rectangular microchannel groove (21) is fixedly arranged in the cavity (13), the upper surface of the microchannel inner plate (2) is tightly attached to the transparent glass cover plate (4), the transparent glass cover plate (4) is covered and pressed by the upper sealing cover plate (5) and is fixed on the base outer plate (1) by using screws, and the L-shaped cover plate (3) of the zigzag miniature isolating plate (31) with the width of 2mm is arranged on the upper surface of the base outer plate (1); cutting off a power supply of the preheating ceramic electric heating sheet (6), maintaining the heating power of the main heating ceramic electric heating sheet (7) to keep the temperature of the heating sheet at about 200 ℃, and continuously heating the working medium along with the continuous flow of the fluid working medium in the thin rectangular microchannel groove (21); when the temperature reaches the self-saturation temperature of 100 ℃, the phenomenon of boiling two-phase flow can occur in the thin rectangular microchannel groove (21); the sensors at the first temperature and pressure measuring hole (16), the second temperature and pressure measuring hole (17) and the third temperature and pressure measuring hole (18) in the micro-channel experimental unit (28) measure the temperature and the pressure of the experimental working medium, a high-speed camera above the experimental device captures image information of a boiling two-phase flow phenomenon in the thin rectangular micro-channel groove (21), and the acquired temperature, pressure and image data are transmitted to a computer for further data analysis.

Technical Field

The invention belongs to the technical field of gas-liquid two-phase flow experiments, in particular to a micro-channel experiment system for inducing two-phase flow, which can be used for the engineering fields of two-phase flow attribute measurement in the energy and power industry, aerospace basic part lubrication design, electronic element heat dissipation and thermal design in the IT industry and the like.

Technical Field

In a system, homogeneous substances having the same physical and chemical properties and the same composition are generally referred to as "phases", and "two-phase flow" refers to a flow system composed of substances in which two different phases exist simultaneously. Two-phase flow phenomenon exists in the engineering application fields of various pumps and pipeline engineering of energy power, aerospace lubrication sealing parts, miniature electronic components in IT information industry and the like, and the research on the property of the two-phase flow and the phase change rule thereof has great significance on the operation stability and reliability of actual engineering systems.

Taking the heat dissipation and thermal design of microelectronic components for information industry as an example, as electronic devices in integrated circuits are developed toward miniaturization and centralization, relatively small physical space has large heat flux density, and conventional heat exchange technology cannot meet the heat dissipation requirements of the existing electronic devices. Because a large amount of heat can be taken away when the liquid is boiled and evaporated, the flow boiling heat exchange technology of gas-liquid two-phase flow becomes a heat dissipation technology mainly adopted by electronic devices at home and abroad at present. The two-phase flow boiling heat exchange technology is based on forced convection, and utilizes the phase change process of medium from liquid state to gas state to absorb a great deal of latent heat of vaporization so as to realize more efficient heat exchange; the method has important guiding significance for the heat dissipation of the miniature electronic element and the thermal design thereof by obtaining the phase change rule of the gas-liquid two-phase flow during flowing boiling.

Most of the current papers and patents related to gas-liquid two-phase flow focus on the field of gas-liquid two-phase flow measurement and experimental methods, and few researches are made on experimental devices of two-phase flow and experimental acquisition methods of phase change laws of the two-phase flow. For example, the patent "two-phase flow measuring device and method combining separated electromagnetic differential pressure in pipe" (number: CN107543586B) discloses a two-phase flow measuring device and method combining separated electromagnetic differential pressure in pipe, the device mainly comprises a measuring pipeline, a cyclone device, an electromagnetic flowmeter, a differential pressure transmitter, etc.; the measuring method uses a cyclone device to enable fluid in a pipe to generate cyclone and generate a phase separation state, uses an electromagnetic flowmeter and a differential pressure transmitter to measure electromagnetic output and differential pressure output related to two-phase flow, and obtains each phase flow of the two-phase flow through simultaneous calculation, thereby forming a combined method based on phase separation and combined with double-parameter measurement. The patent "two-phase flow velocity sound electric bimodal measurement method" (number: CN105181996B) discloses a two-phase velocity sound electric bimodal measurement method which can accurately measure the average flow velocity and the phase separation ratio of two-phase flow in a pipeline. The patent ERT-based homogeneous gas-liquid mixed two-phase flow testing method and system (number: CN110108331A) discloses a gas-liquid mixed two-phase flow testing method, which solves the problem of gas-liquid flow measurement when homogeneous gas-liquid mixed two-phase flow is not separated; meanwhile, the patent 'a content measuring device of gas-liquid two-phase flow' (number: CN212083156U) discloses a content measuring device of gas-liquid two-phase flow, which solves the problem that the existing measuring equipment can not measure the content of the two-phase flow on line in real time, simplifies the process procedure of content measurement and realizes the real-time on-line accurate measurement of the gas-liquid two-phase flow; the youchen proposes and measures the two-phase flow pattern based on the electrical resistance tomography technology, and indirectly obtains other two-phase flow parameters (youchen. positive and negative problems of two-phase flow measurement based on the ERT technology and experimental research [ D ]. SiAn electronic technology university, 2020.)

The above patents and papers focus on the acquisition of two-phase flow properties, such as flow rate, viscosity, flow pattern characteristics, etc.; the two-phase flow is generated by actual working conditions or directly mixed liquid and gas, and the simulation process of directly mixing liquid, gas and liquid and then gas is lacked, and the mechanism of the induction process is very complex. Therefore, the research on a device and a system for inducing the gas-liquid phase change has important scientific significance and engineering guidance value for deeply knowing the mechanism of gas-liquid two-phase flow generation and the phase change mechanism thereof.

Disclosure of Invention

Aiming at the current situation that the existing gas-liquid two-phase flow mechanism research lacks an experimental device, the invention provides a micro-channel experimental system capable of inducing two-phase flow so as to induce two different types of two-phase flow phenomena including boiling and flash evaporation two-phase flow, and simultaneously can induce the working condition and the structural parameter range of the two-phase flow phenomenon through configured experimental device parts with different parameters according to different experimental requirements.

The invention aims to realize the purpose, and the micro-channel experimental system for inducing the two-phase flow is characterized in that: at least comprises the following steps: the device comprises a high-pressure liquid storage tank (8), a magnetic gear pump (9), a flow valve (10), a microporous filter element (26), a flowmeter (27), a microchannel experiment unit (28), a condensation unit (29), loop auxiliary equipment (30) and a data acquisition unit (32); the high-pressure liquid storage tank (8), the magnetic gear pump (9), the flow valve (10), the microporous filter element (26), the flowmeter (27), the micro-channel experiment unit (28) and the condensation unit (29) are connected in series to form a loop, the micro-channel experiment unit (28) is connected with loop auxiliary equipment (30) and a data acquisition unit (32), wherein the high-pressure liquid storage tank (8) is a closed container capable of bearing certain high pressure and is used for containing experiment working media; the top of the high-pressure liquid storage tank (8) is provided with a pressure measuring and controlling device and an exhaust valve; a transparent glass tube water level gauge is arranged on one side of the tank body;

the magnetic gear pump (9) drives the working medium in the experimental loop to flow; the flow meter (27) is used for accurately measuring the flow rate of the fluid in the loop;

the flow valve (10) is a valve for controlling the on-off of the whole loop;

the diameter of the micropores in the microporous filter core (26) is 4-10 μm, so that solid impurities in a loop can be prevented from entering an experimental device;

the micro-channel experiment unit (28) is the body of the invention;

the condensing unit (29) is composed of a plate heat exchanger and a low-temperature cold water bath tank, and the condensing unit (29) is used for cooling the fluid working medium flowing out of the micro-channel experimental section to reduce the temperature of the fluid working medium to an original temperature value in the liquid storage tank;

the circuit auxiliary device (30) comprises at least: the high-speed camera is arranged right above the micro-channel experimental device and can shoot and observe the flowing boiling condition in the micro-channel, the flow pattern change of fluid and the flash boiling in the buffer cavity (14) in the experimental device through the transparent glass cover plate (4), and the LED light source is arranged beside the high-speed camera to irradiate the experimental device, so that the picture shot by the high-speed camera is clearer; the data acquisition part mainly comprises a data acquisition instrument and a computer, and the mainly acquired data comprise the temperature and pressure of 3 measuring points in the experimental device, the flow data in the magnetic flowmeter and the image data shot in a high-speed camera erected above the experimental device.

The experimental working medium in the high-pressure liquid storage tank (8) is deionized water or ethanol liquid, a heater in the liquid storage tank is started in advance before an experiment to carry out advanced heating boiling treatment on the experimental working medium in the liquid storage tank so as to remove non-condensable gas in the fluid working medium in the whole experimental loop, and the whole experiment is started after the temperature of the fluid working medium in the liquid storage tank is reduced to normal temperature after boiling degassing.

Fluid working media in the loop flow through the microporous filter element (26) and the flowmeter (27) under the drive of the magnetic gear pump (9) and then enter the micro-channel experimental unit (28), boiling and flash evaporation two-phase flow is induced in the micro-channel experimental unit (28) and then flows out, and then the fluid working media flow through the condensing unit 29, are cooled by heat dissipation of the plate heat exchanger and finally flow back to the high-pressure liquid storage tank (8).

The microchannel experimental unit (28) at least comprises: the device comprises a base outer plate (1), a micro-channel inner plate (2), an L-shaped cover plate (3) and an auxiliary component; the auxiliary component includes clear glass apron (4), goes up sealed apron (5), preheats ceramic electric heating plate (6), main heating ceramic electric heating plate (7), base planking (1) is the rectangle cuboid that has the cavity in, wholly adopts the material that heat conductivility is good, and it has rectangle microchannel entry (11) to distribute in proper order to the other end from rectangle cuboid one end, planking microchannel entry (19), planking microchannel (12), cavity (13), cushion chamber (14), circular channel export (15), includes three temperature pressure survey hole in rectangle cuboid one side, and three temperature pressure survey hole is respectively: a first temperature and pressure measuring hole (16), a second temperature and pressure measuring hole (17) and a third temperature and pressure measuring hole (18), wherein the first temperature and pressure measuring hole (16) is close to the rectangular microchannel inlet (11) but forms a vertical structure with the microchannel inlet (11), and the second temperature and pressure measuring hole (17) is positioned at the joint of the tail end of the outer plate microchannel (12) and the cavity (13); the third temperature and pressure measuring hole (18) is close to the buffer cavity (14) and communicated with the buffer cavity (14).

The microchannel inlets (11) are working medium inlet channels of the whole experimental device, are distributed on the side surface of the outer plate of the base at equal intervals, are in thin rectangles, and the number N is 6; the micro-channel inlet (11) is externally connected in the experimental loop and used as an inlet channel of the device to convey the experimental working medium into the micro-channel experimental device;

the outer plate microchannel (12) is of a 6 channel groove structure which is arranged at equal intervals, the cross section of the outer plate microchannel is in a thin rectangle shape which is the same as that of the microchannel inlet (11), and the outer plate microchannel is positioned on the upper surface of the outer plate (1) of the base; the width of the outer plate microchannel (12) is 10mm, the depth is 4mm, the outer plate microchannel is communicated with the microchannel inlet (11) and the cavity (13), and the fluid working medium is conveyed to the cavity (13) from the microchannel inlet (11);

the outer plate micro-channel inlet (19) is a structure formed by connecting a micro-channel inlet (11) and an outer plate micro-channel (12) and is a structure formed by six rectangular inlets which are arranged at equal intervals, the cross section size of the outer plate micro-channel inlet is the same as that of the micro-channel inlet (11), and working medium flows into the outer plate micro-channel (12) through the structure.

The cavity (13) is a cuboid cavity with an opening on the upper surface and is positioned in the center of the base outer plate (1), and the upper surface of the cavity is flush with the upper surface of the base outer plate (1);

the buffer cavity (14) is a cuboid cavity with an opening on the upper surface and is a partial cavity reserved between the outlet (15) of the round channel of the experimental device and the cavity (13), the upper surface of the buffer cavity (14) is still flush with the upper surface of the outer plate (1) of the base, but the depth and the length of the buffer cavity are smaller than those of the cavity (13), step section mutation is formed at the joint of the cavity (13) and the buffer cavity (14), and the buffer cavity (14) can be used as an external environment lower than the saturated vapor pressure of the flowing medium in the channel to provide a space for the flash evaporation and boiling of the flowing medium in the device;

the circular channel outlet (15) is an outlet of a fluid working medium in the whole device, and the cross section of the circular channel outlet is circular; the first temperature pressure measuring hole (16), the second temperature pressure measuring hole (17) and the third temperature pressure measuring hole (18) are measuring holes with the diameter of 6mm, are distributed on the side of the micro-channel experimental device and are used as pressure and temperature measuring points; a temperature sensor and a pressure sensor are arranged in the measuring hole of the device for measuring the pressure and the temperature of the fluid working medium in the experimental device respectively; wherein the first temperature and pressure measuring hole (16) is close to the inlet (11) of the micro-channel and is communicated with the channel on the side of the device to measure the inlet temperature and pressure of the working medium in the device; the second temperature and pressure measuring hole (17) is positioned at the tail end of the outer plate microchannel, is connected with the microchannel on the side of the device, and is used for measuring the temperature and the pressure of the working medium which is about to leave the outer plate microchannel (12); the third temperature and pressure measuring hole (18) is close to the outlet (15) of the circular channel of the device, is communicated with the cavity (13), and measures the pressure and the temperature of the working medium flowing out of the micro-channel and entering the cavity (13); the pressure sensor and the temperature sensor are arranged in a first temperature and pressure measuring hole (16), a second temperature and pressure measuring hole (17) and a third temperature and pressure measuring hole (18), and the measuring holes provided with the sensors are sealed by sealant;

the micro-channel inner plate (2) is of a cuboid structure, the whole body is made of copper alloy materials with good heat transfer performance, the size (length multiplied by width multiplied by height) of the micro-channel inner plate (2) is the same as that (length multiplied by width multiplied by height) of the cavity (13), the micro-channel inner plate (2) and the cavity (13) are in interference fit during actual installation, the micro-channel inner plate (2) is fixed in the cavity (13), and the upper surface of the micro-channel inner plate is flush with the upper surface of the cavity (13); n microchannel grooves (20) are distributed on the upper surface of the microchannel inner plate (2) at equal intervals, the number n of the microchannel grooves (20) is usually the same as the number of the microchannel grooves (12) of the outer plate, and n belongs to {2,3,4,5,6 }, and the number can be adjusted according to actual experiments; the microchannel groove (20) is communicated with the outer plate microchannel groove (12), and the working medium flows into the microchannel groove of the inner plate (2) after flowing through the outer plate microchannel groove (12).

The microchannel groove (20) is of a thin rectangular microchannel groove (21) structure, or is an arc microchannel groove (22) or a step section microchannel groove (23) or a spray pipe microchannel groove (24) or a thin rectangular double-channel groove (25).

The preheating ceramic electric heating plate (6) is positioned under the outer plate micro-channel (12) and close to an inlet (19) of the outer plate micro-channel, and is used as a heat source of a preheating part to heat and pretreat liquid working media entering the device; the main heating ceramic electric heating sheet (7) is positioned right below the microchannel inner plate (2) and used as a main heating part of the experimental device to heat working media flowing into the microchannel of the inner plate, so that a boiling two-phase flow phenomenon of liquid working media in the microchannel groove (20) is induced; wherein the preheating ceramic electric heating plate (6) and the main heating ceramic electric heating plate (7) are externally connected with a direct current power supply to respectively adjust different heating powers; wherein, the ceramic electric heating sheets (6) for preheating and the ceramic electric heating sheets (7) for main heating are separated by a distance of 30mm-40mm to prevent the two ceramic electric heating sheets from having larger mutual interference when working at the same time.

One side of the L-shaped cover plate (3) is provided with a zigzag micro isolation plate (31) which can partially shield the inlet (19) of the outer plate micro-channel so as to change the working medium pressure entering the outer plate micro-channel (12) and the thin rectangular micro-channel groove (21) and perform gradient adjustment to the working medium pressure in the micro-channel to a certain degree; working medium flows into the outer plate microchannel (12) from the outer plate microchannel inlet (19) and then flows into the inner plate microchannel (2) through the outer plate microchannel (12), wherein the preheating ceramic electric heating sheet (6) is positioned at the lower position of the outer plate microchannel (12) and serves as a preheating heat source in an experiment, and the preheating treatment is carried out on the working medium when the working medium enters the microchannel device and does not flow into the microchannel groove (20).

Compared with the prior device, the invention has the following advantages:

1. the invention relates to a micro-channel experimental method for inducing two-phase flow, which adopts a scheme that an outer plate and an inner plate of a base are separated, and aims to change the shape, the number, the arrangement mode and other changes of micro-channels only by disassembling the inner plate under the condition of not changing an integral loop of an experiment.

2. The invention can replace the actual inner plate of the micro-channel, so that the micro-channel can achieve the effect of simulating a thin spray pipe, and when the fluid working medium flows out of the micro-channel, the flash evaporation boiling two-phase flow phenomenon can be generated in the buffer cavity 14 of the device.

3. The microchannel experimental device is provided with the replaceable L-shaped copper plate cover plate, the cover plate is provided with a convex isolation plate structure 31 for shielding the microchannel inlet channel 19 of the outer plate of the microchannel, and the working medium pressure of fluid entering the microchannel can be adjusted within a certain range by changing the sectional area of the inlet structure of the outer plate microchannel.

Drawings

FIG. 1 is a view showing the structure of an overall experimental apparatus;

FIG. 2 is a view showing the structure of an outer panel;

FIG. 3 is a thin rectangular microchannel inner plate;

FIG. 4 is an arcuate microchannel inner plate;

FIG. 5 is a stepped microchannel inner plate;

FIG. 6 is a nozzle type microchannel inner plate;

FIG. 7 is a two-channel microchannel inner plate;

FIG. 8 is an L-shaped thin copper sheet cover plate;

FIG. 9 is a schematic view of the inlet structure of the microchannel of the outer plate;

FIG. 10 is a schematic view of an L-shaped thin copper sheet cover plate covering the inlet of the microchannel of the outer plate;

fig. 11 is an experimental circuit diagram of the experimental device access.

In the figure, 1, a base outer plate; 2. a microchannel inner plate; 3. an L-shaped cover plate; 4. a transparent glass cover plate; 5. an upper sealing cover plate; 6. preheating a ceramic electric heating sheet; 7. a main heating ceramic electric heating sheet; 8. a high-pressure liquid storage tank; 9. a magnetic gear pump; 10. a flow valve; 11. a microchannel inlet; 12. an outer plate microchannel; 13. a cavity; 14. a buffer chamber; 15. a circular channel outlet; 16. a first temperature and pressure measurement hole; 17. a second temperature and pressure measurement hole; 18. a third temperature and pressure measurement hole; 19. an outer plate microchannel inlet; 20. a microchannel slot; 21. a thin rectangular microchannel slot; 22. an arcuate microchannel slot; 23. a stepped section channel slot; 231. (ii) a mutant structure; 24. a nozzle microchannel slot; 241. (ii) a mutant structure; 25. double thin rectangular microchannel slots; 26. a microporous filter element; 27. a flow meter; 28. a microchannel experimental unit; 29. a condensing unit; 30. a loop auxiliary device; 31. a zigzag micro-spacer; 32. and a data acquisition unit.

Detailed Description

The invention is described in further detail below with reference to the following figures and specific examples:

example 1

Experimental device for inducing boiling two-phase flow phenomenon on thin rectangular microchannel

Referring to fig. 1 and 2, a microchannel device for inducing two-phase flow includes at least: the device comprises a base outer plate 1, a micro-channel inner plate 2, an L-shaped cover plate 3 and an auxiliary component; the auxiliary components comprise a transparent glass cover plate 4, an upper sealing cover plate 5, a preheating ceramic electric heating plate 6 and a main heating ceramic electric heating plate 7.

As shown in fig. 2, base planking 1 is the rectangle cuboid that has the cavity in, wholly adopts the (copper alloy) material that thermal conductivity is good, has distributed microchannel entry 11, planking microchannel entry 19, planking microchannel 12, cavity 13, cushion chamber 14, circular channel export 15 from rectangle cuboid one end to the other end in proper order, includes three temperature pressure survey hole in rectangle cuboid one side, and three temperature pressure survey hole is respectively: a first temperature pressure measuring hole 16, a second temperature pressure measuring hole 17 and a third temperature pressure measuring hole 18, wherein the first temperature pressure measuring hole 16 is close to the microchannel inlet 11 but forms a vertical structure with the microchannel inlet 11, and the second temperature pressure measuring hole 17 is communicated with the joint of the outer plate microchannel 12 and the cavity 13; the third temperature and pressure measuring hole 18 is adjacent to the buffer chamber 14 and communicates with the buffer chamber 14.

The microchannel inlets 11 are working medium inlet channels of the whole experimental device, are distributed on the side surface of the outer plate of the base at equal intervals, are in thin rectangles, and the number N is 6; the micro-channel inlet 11 is externally connected in an experimental loop and used as an inlet channel of the device to convey an experimental working medium into the micro-channel experimental device;

the outer plate microchannel 12 is of a 6-channel groove structure arranged at equal intervals, the cross section of the outer plate microchannel is in a thin rectangle shape which is the same as that of the microchannel inlet 11, and the outer plate microchannel is positioned on the upper surface of the outer plate 1 of the base. The width of the outer plate microchannel is 10mm, the depth is 4mm, the outer plate microchannel is communicated with the microchannel inlet 11 and the cavity 13, and fluid working media are conveyed to the cavity 13 from the microchannel inlet 11;

as shown in FIG. 9, the inlet channel 19 of the outer plate microchannel is a structure in which the inlet 11 of the microchannel experimental device is connected with the outer plate microchannel 12, and is a structure of six rectangular inlets arranged at equal intervals, the cross-sectional dimension (length × width) of the inlet channel is the same as the cross-sectional dimension of the inlet 11 of the microchannel, and the working medium flows into the outer plate microchannel 12 through the structure.

The cavity 13 is a cuboid cavity with an opening on the upper surface, is positioned in the center of the base outer plate 1, and the upper surface of the cavity is flush with the upper surface of the base outer plate 1;

referring to fig. 2, the buffer cavity 14 is a rectangular parallelepiped cavity with an open upper surface, and is a partial cavity left between the circular channel outlet 15 and the cavity 13, the upper surface of the buffer cavity 14 is still flush with the upper surface of the base outer plate 1, but the depth and the length of the buffer cavity are smaller than those of the cavity 13, a step section mutation exists at the joint of the cavity 13 and the buffer cavity 14, and the buffer cavity 14 can be used as an external environment lower than the saturated vapor pressure of the flowing working medium in the channel to provide a space for the flowing working medium in the device to flash and boil;

the circular channel outlet 15 is an outlet of a fluid working medium in the whole device, and the cross section of the circular channel outlet is circular; the first temperature pressure measuring hole 16, the second temperature pressure measuring hole 17 and the third temperature pressure measuring hole 18 are measuring holes with the diameter of 6mm, are distributed on the side of the micro-channel experimental device and are used as pressure and temperature measuring points; the measuring hole is provided with a temperature sensor and a pressure sensor which respectively measure the pressure and the temperature of the fluid working medium in the experimental device. Wherein, the first temperature and pressure measuring hole 16 is close to the micro-channel inlet 11 and is communicated with the channel at the side of the device, and the inlet temperature and pressure of the working medium in the device are measured; the second temperature and pressure measuring hole 17 is positioned at the tail end of the outer plate microchannel, is connected with the microchannel at the side of the device, and is used for measuring the temperature and the pressure of the working medium which is about to leave the outer plate microchannel 12; the third temperature and pressure measuring hole 18 is close to the round channel outlet 15, is communicated with the cavity 14 and measures the pressure and the temperature of the working medium flowing out of the micro channel and entering the cavity 14; the pressure sensor and the temperature sensor are arranged in a first temperature and pressure measuring hole 16, a second temperature and pressure measuring hole 17 and a third temperature and pressure measuring hole 18, and the measuring holes provided with the sensors are sealed by sealant;

the micro-channel inner plate 2 is of a cuboid structure and is integrally made of a copper alloy material with good heat transfer performance, the size (length multiplied by width multiplied by height) of the micro-channel inner plate 2 is the same as that of the cavity 13 (length multiplied by width multiplied by height), the micro-channel inner plate 2 and the cavity 13 are in interference fit during actual installation, the micro-channel inner plate 2 is fixed in the cavity 13, and the upper surface of the micro-channel inner plate 2 is flush with the upper surface of the cavity 13; n microchannel grooves 20 are distributed on the upper surface of the microchannel inner plate 2 at equal intervals, the number n of the microchannel grooves 20 is usually the same as the number of the microchannel grooves 12 of the outer plate, and n belongs to {2,3,4,5,6 }, and the number can be adjusted according to actual experiments. The thin rectangular microchannel groove 21 is communicated with the outer plate microchannel groove 12, and the working medium flows into the microchannel groove of the inner plate after flowing through the outer plate microchannel groove 12.

Referring to fig. 3, fig. 3 shows six microchannel grooves 20 of the same size distributed at equal intervals, the microchannel grooves 20 are of a thin rectangular microchannel groove 21 structure, the size (depth × width) of the channel of the thin rectangular microchannel groove 21 is the same as the size of the microchannel 12 of the outer plate, the number is six as the number of the microchannel 12 of the outer plate, the spatial position is the same as the position where the microchannel 12 of the outer plate is distributed, and the flowing working medium flows into the thin rectangular microchannel groove 21 through the microchannel 12 of the outer plate in the microchannel experimental device;

referring to fig. 4, fig. 4 shows six equal-sized microchannel grooves 20 distributed at equal intervals, the microchannel grooves 20 are arc-shaped microchannel grooves 22, the depth of the microchannel of the arc-shaped microchannel grooves 22 is slightly larger than that of the microchannel of the outer plate, and the channel section is not rectangular but circular arc.

Referring to fig. 5, fig. 5 shows six equal-sized microchannel grooves 20 distributed at equal intervals, the microchannel grooves 20 are stepped channel grooves 23, the front and rear sections of the stepped channel grooves 23 have different depths, the front section is connected with the outer plate microchannel groove 12 and has the same depth as the outer plate microchannel groove 12, and the rear section is connected with the cavity 14 and has half of the depth of the front section. The channel has a stepped configuration therein as shown by configuration 231 in figure five.

The microchannel grooves 20 are either nozzle channel grooves 24, as shown in fig. 6, fig. 6 shows six nozzle channel grooves 24 distributed at equal intervals, the front ends of the nozzle channel grooves 24 are connected with the outer plate channel grooves 12 and have the same depth, and the rear ends of the nozzle channel grooves 24 are provided with structures 241 for shielding the microchannels. Wherein the structure 241 seals the microchannel leaving only a small outlet in the middle. The outlet is a small circular outlet with a diameter of 0.5mm, which acts like a thin lance. When the fluid working medium is released into the buffer cavity 14 through the outlet, a two-phase flow phenomenon that the working medium is subjected to flash boiling in the buffer cavity 14 can be induced.

The microchannel slots 20 are either thin rectangular dual channel slots 25. referring to fig. 7, fig. 7 shows that the microchannel slots 20 are two equally spaced double thin rectangular microchannel slots 25 of the same size, and the single double thin rectangular microchannel slot 25 is the same size (depth x width) as the thin rectangular microchannel slot 21, but the number of channels is different.

A transparent glass cover plate 4 is arranged above the micro-channel inner plate 2, as shown in fig. 1, and is a transparent and high-temperature-resistant glass cover plate, and is fixedly arranged above the cavity 13 and the buffer cavity 14 and attached to the upper surface of the base outer plate 1.

During actual installation, the lower surface of the transparent glass cover plate 4 is tightly attached to the upper surface of the inner micro-channel plate 2, and sealant can be used for processing the gap. Meanwhile, as the transparent glass cover plate 4 is made of transparent glass, the flowing condition of the working medium in the microchannel can be observed through the transparent glass cover plate 4 in the experiment; an upper sealing cover plate 5 is arranged above the transparent glass cover plate 4, and the upper sealing cover plate 5 is a thin rectangular metal plate with a hollow middle. The size (length multiplied by width) of the outer edge of the upper sealing cover plate 5 is the same as the size (length multiplied by width) of the base outer plate 1, and the size (length multiplied by width) of the middle hollow rectangle is the same as the size (length multiplied by width) of the cavity 13 in the base outer plate 1 and the size (length multiplied by width) of the whole body cavity of the buffer cavity 14. The upper sealing cover plate 5 is connected and fixed with the base outer plate 1 through screws, and the upper sealing cover plate 5 is equivalent to a pressing plate for fixedly pressing the transparent glass cover plate 4, so that the stability of the inner plate 2 of the micro-channel and the stability of the whole micro-channel experimental device are ensured.

Referring to fig. 8, the base outer plate 1 is covered with an L-shaped cover plate 3 near the inlet 11 of the microchannel, and the L-shaped cover plate 3 is a rectangular thin copper plate cover plate fixedly mounted on the upper surface of the base outer plate 1 by screws; one side of the L-shaped cover plate 3 is equally spaced with 6 similar zigzag micro isolation plates 31, the position distribution of the zigzag micro isolation plates 31 is aligned with the space position of the outer plate micro channel inlet channel 19, the outlet section of the outer plate micro channel inlet channel 19 is partially shielded, and thus the pressure of the fluid working medium flowing into the outer plate micro channel 12 is changed. The height of the micro-partition plate 31 is the same as the depth of the outer plate microchannel 12, and the width does not exceed the width of the outer plate microchannel inlet channel 19, so that the micro-partition plate 31 only partially shields the outer plate microchannel inlet channel 19; the micro-isolation plate 31 on the L-shaped cover plate 3 is used as a structure for changing the pressure of the fluid working medium flowing into the outer plate microchannel 12, and the structure can shield the channel section at the inlet channel 19 of the outer plate microchannel of the microchannel to a certain degree, thereby adjusting the pressure of the fluid working medium entering the outer plate microchannel 12. When different L-shaped cover plates 3 are replaced, the pressure of the working medium in the micro-channel can be adjusted. The pressure regulation is realized by changing the width of the zigzag micro-partition plate 31 in the L-shaped cover plate 3, so that the gradient pressure regulation is only carried out on the working medium entering the micro-channel within a certain range.

A preheating ceramic electric heating plate 6 and a main heating ceramic electric heating plate 7 are fixedly arranged below the upper sealing cover plate 5, and are shown in reference to fig. 9 and 10; the preheating ceramic electric heating plate 6 is positioned right below the outer plate microchannel 12 and close to an inlet 19 of the outer plate microchannel, and is used as a heat source of a preheating part for heating and pretreating liquid working media entering the device; the main heating ceramic electric heating sheet 7 is positioned right below the micro-channel inner plate 2 and used as a main heating part of the experimental device to heat working media flowing into the micro-channel of the inner plate 3, so that a boiling two-phase flow phenomenon of liquid working media in the micro-channel of the inner plate 2 is induced; wherein the preheating ceramic electric heating plate 6 and the main heating ceramic electric heating plate 7 are externally connected with a direct current power supply to respectively adjust different heating powers; wherein, the ceramic electric heating sheets 6 for preheating and the ceramic electric heating sheets 7 for main heating are separated by a distance of 30mm-40mm, so as to prevent the two ceramic electric heating sheets from having larger mutual interference when working at the same time.

FIG. 11 is a schematic diagram of a closed cycle microchannel flow boiling experimental system; as shown in fig. 11, a microchannel device for inducing two-phase flow, comprises: the device comprises a high-pressure liquid storage tank 8, a magnetic gear pump 9, a flow valve 10, a microporous filter element 26, a flowmeter 27, a microchannel experiment body 28, a condensation unit 29, a loop auxiliary device 30 and a data acquisition unit 32; the high-pressure liquid storage tank 8, the magnetic gear pump 9, the flow valve 10, the microporous filter element 26, the flowmeter 27, the microchannel experiment body 28 and the condensing unit 29 are connected in series to form a loop, and the microchannel experiment body 28 is connected with loop auxiliary equipment 30 and a data acquisition unit 32, wherein the high-pressure liquid storage tank 8 is a closed container capable of bearing certain high pressure and is used for containing experiment working media; the top of the high-pressure liquid storage tank 8 is provided with a pressure measuring and controlling device and an exhaust valve; a transparent glass tube water level gauge is arranged on one side of the tank body;

the magnetic gear pump 9 drives the working medium in the experimental loop to flow; the flow meter 27 is used for accurately measuring the flow rate of the fluid in the loop;

the flow valve 10 is a valve for controlling the on-off of the whole loop;

the diameter of the micropores in the microporous filter element 26 is 4-10 μm, so that solid impurities in a loop can be prevented from entering the experimental device;

the micro-channel experiment body 28 is the body of the invention;

the condensing unit 29 is composed of a plate heat exchanger and a low-temperature cold water bath tank, and the condensing unit 29 is used for cooling the fluid working medium flowing out of the microchannel experimental section to reduce the temperature of the fluid working medium to an original temperature value in the liquid storage tank;

the loop back assistance device 30 comprises at least: the high-speed camera is arranged right above the micro-channel experimental device and can shoot and observe the flowing boiling condition, the flow pattern change of fluid and the flash boiling in the buffer cavity in the micro-channel experimental device through the transparent glass cover plate 4, and the LED light source is arranged beside the high-speed camera to irradiate the experimental device, so that the picture shot by the high-speed camera is clearer; the data acquisition part mainly comprises a data acquisition instrument and a computer, and the mainly acquired data comprise the temperature and pressure of 3 measuring points in the experimental device, the flow data in the magnetic flowmeter and the image data shot in a high-speed camera erected above the experimental device.

The experimental working medium in the high-pressure liquid storage tank 8 can be selected from deionized water or ethanol and other liquids, a heater in the liquid storage tank is started in advance before the experiment to carry out advanced heating boiling treatment on the experimental working medium in the liquid storage tank so as to remove non-condensable gas in the fluid working medium in the whole experiment loop, and the whole experiment is started after the temperature of the fluid working medium in the liquid storage tank is reduced to normal temperature after boiling degassing.

The fluid working medium in the loop flows through the microporous filter element 26 and the flowmeter 27 under the driving of the magnetic gear pump 9, enters the micro-channel experiment body 28, is induced to generate boiling and flash two-phase flow in the micro-channel experiment body 28, flows out, flows through the condensing unit 29, is cooled by heat dissipation of the plate heat exchanger, and finally flows back to the high-pressure liquid storage tank 8.

The invention induces and produces boiling and flash evaporation two-phase flow phenomena, uses deionized water as fluid working medium in the experiment, the microchannel device of the invention is connected into the whole closed circulation experiment loop, the normal temperature deionized water enters the microchannel experiment body 28 through the experiment loop through the rectangular channel inlet 11, there are three measuring holes installed with temperature and pressure sensors near the microchannel inlet 11, respectively: a first temperature pressure measuring hole 16, a second temperature pressure measuring hole 17 and a third temperature pressure measuring hole 18, wherein the first temperature pressure measuring hole 16 measures the temperature and the pressure of the working medium which just enters the micro-channel experimental device for the first time, and deionized water flows to an outer plate micro-channel inlet channel 19 from a rectangular channel, and a detachable L-shaped cover plate 3 is arranged at the position; one side of the L-shaped cover plate 3 is provided with a raised micro-partition plate structure 31 which can partially shield the inlet channel 19 of the outer plate microchannel so as to change the working medium pressure entering the outer plate microchannel 12 and the thin rectangular microchannel groove 21 and perform gradient adjustment to the working medium pressure in the microchannel to a certain degree. Working medium flows into the outer plate microchannel 12 from the outer plate microchannel inlet channel 19, and then flows into the inner plate 2 microchannel through the outer plate microchannel 12, wherein the ceramic electric heating sheet 6 is positioned at the lower position of the outer plate microchannel 12 and serves as a preheated heat source in the experiment. The working fluid is pre-heated when it enters the microchannel apparatus and does not flow into the thin rectangular microchannel slots 21. Near the end of the outer plate microchannel 12 there is a second temperature and pressure measurement port 17 for the temperature and pressure sensor mounting where a second measurement of the temperature and pressure of the working fluid that has just entered the thin rectangular microchannel slot 21 can be made. When the L-shaped cover plate 3 is replaced and the power of the ceramic electric heating sheet 6 is adjusted, the pressure and the temperature of the fluid working medium entering the micro channel of the inner plate 2 can be regulated, and the temperature and the pressure values can be accurately measured through the sensor in the second temperature and pressure measuring hole 17. The ceramic electric heating sheet 7 is located right below the cavity 13, and is used as a heat source for heating the inner plate 2 in an experiment to heat inner plate micro-channels such as the thin rectangular micro-channel groove 21, the arc micro-channel groove 22 and the like. The ceramic electric heating plate 7 is externally connected with a direct current power supply to control the heating power. The rear of the micro-channel inner plate 2 is a buffer cavity 14, and the working medium flows into the buffer cavity 14 through the micro-channel on the inner plate 2 and then flows out of the micro-channel experimental device through a circular channel outlet 15. A third temperature and pressure measuring opening 18 is provided near the circular channel outlet 15, in which a temperature and pressure sensor is mounted, wherein a third measurement of the temperature and pressure of the working medium that is about to flow out of the test device can be carried out.

The inner plate of the thin rectangular microchannel 21 is installed and fixed in the cavity 13, the upper surface of the heating inner plate 2 is tightly attached to the transparent glass cover plate 4, the transparent glass cover plate 4 is covered and compressed by the upper sealing cover plate 5 and is fixed on the base outer plate 1 by using screws, and the L-shaped cover plate 3 using the isolation plate 31 with the width of 2mm is installed on the upper surface of the base outer plate 1. The power supply of the ceramic heating sheet 6 is cut off, the heating power of the ceramic electric heating sheet 7 is maintained, the temperature of the heating sheet is maintained at about 200 ℃, and the working medium is continuously heated along with the continuous flowing of the fluid working medium in the thin rectangular microchannel groove 21. When the temperature reaches the self-saturation temperature of 100 ℃, the phenomenon of boiling two-phase flow can occur in the rectangular microchannel slot 21; the sensors at the first temperature and pressure measuring hole 16, the second temperature and pressure measuring hole 17 and the third temperature and pressure measuring hole 18 in the micro-channel experiment body 28 measure the temperature and the pressure of the experiment working medium, a high-speed camera above the experiment device captures the image information of the boiling two-phase flow phenomenon in the micro-channel 21, and the acquired temperature, pressure and image data are transmitted to a computer for further data analysis.

The microchannel experimental device described above was still used, and only the heating power of the ceramic heating plate was changed. The power supply of the ceramic electric heating plate 6 is cut off, the heating power of the ceramic electric heating plate 7 is maintained, the temperature of the heating plate is maintained at about 350 ℃, and the micro-channel experimental device is continuously heated. When the fluid working medium flows into the thin rectangular microchannel groove 21 from the outer plate channel 12, because the temperature of the inner plate is overhigh at the moment, the supercooling boiling two-phase flow phenomenon occurs at the moment that the liquid working medium contacts the inner plate; the liquid working medium is subjected to violent boiling on the wall surface of the thin rectangular microchannel groove 21 and is rapidly evaporated into gas, meanwhile, disordered small bubbles are generated on the wall surface of the thin rectangular microchannel groove 21, and the bubbles gradually become small until disappear due to cooling in the process that the small bubbles are separated from the wall surface and rise and flow in the microchannel. Subsequently, as the liquid working medium flows in the thin rectangular microchannel groove 21, the working medium in the microchannel slowly rises until reaching the saturation temperature, and the liquid working medium in the microchannel still generates a saturated boiling phenomenon after reaching the saturation temperature; the sensors at the first temperature pressure measuring hole 16, the second temperature pressure measuring hole 17 and the third temperature pressure measuring hole 18 in the experimental device measure the temperature and the pressure of the experimental working medium, a high-speed camera above the experimental device captures image information of a boiling two-phase flow phenomenon in the thin rectangular microchannel groove 21, and the acquired temperature, pressure and image data are transmitted to a computer for further data analysis.

Example 2

Inducing boiling two-phase flow on the arc micro-channel.

Detailed description of the experimental setup and experimental operation procedure referring to the above example 1, the inner plate of the arc-shaped microchannel 22 is used instead, and other operation conditions are the same as those of the first example; the specific differences are as follows:

the inner plate of the arc-shaped micro-channel 22 is installed and fixed in the cavity 13 and covered with a transparent glass cover plate 4, the transparent glass cover plate 4 is covered and pressed by an upper sealing cover plate 5 and is fixed on the base outer plate 1 by screws. Similarly to example 1, the L-shaped cover sheet 3, which still uses the spacer 31 having a width of 2mm, is attached to the upper surface of the base outer panel 1, and the power supply to the ceramic heater chip 6 is cut off to maintain the heating power of the ceramic electric heater chip 7 so that the temperature of the heater chip is maintained at about 200 ℃. With the continuous flow of the fluid working medium in the spray pipe micro-channel 22, the working medium is continuously heated, and a phenomenon of saturated boiling two-phase flow can occur in the spray pipe micro-channel 22 when the self saturation temperature reaches 100 ℃; because the micro-channel of the spray pipe is changed from a rectangle to a circular arc at the moment, the two-phase flow phenomenon of saturated boiling in the micro-channel is different from that in the example 1;

the heating power of the ceramic heating plate is changed, the heating power of the ceramic electric heating plate 7 is maintained, the temperature of the heating plate is maintained at about 350 ℃, and the supercooling boiling two-phase flow phenomenon occurs at the moment that the liquid working medium contacts the inner plate 2 due to the overhigh temperature of the inner plate 2 at the moment when the liquid working medium flows into the spray pipe micro-channel 22 from the outer plate channel 12. The liquid working medium is vigorously boiled on the wall surface of the micro-channel 32 and is rapidly evaporated into gas, meanwhile, disordered small bubbles are generated on the wall surface of the micro-channel 22, and the small bubbles are gradually reduced until disappear due to cooling along with the process of rising in a vertical space after being separated from the wall surface. Then, along with the continuous flow of the liquid working medium into the micro-channel 22 of the spray pipe, the working medium in the channel is slowly heated until reaching the saturation temperature, and the saturated boiling phenomenon still occurs; as in example 1, the temperature and pressure of the experimental working medium are measured by the sensors at the first temperature and pressure measuring hole 16, the second temperature and pressure measuring hole 17 and the third temperature and pressure measuring hole 18 in the experimental device, the image information of the boiling two-phase flow phenomenon in the microchannel 22 is captured by the high-speed camera above the experimental device, and the acquired temperature, pressure and image data are transmitted to the computer for further analysis.

Example 3

The two-phase boiling flow is induced on the stepped micro-channel.

Detailed description of experimental apparatus and experimental operation flow referring to the above example 1, the inner plate of the stepped microchannel 23 is used instead, the power supply of the ceramic electric heating plate 7 is cut off, and the heating power of the ceramic electric heating plate 6 is maintained to maintain the temperature of the heating plate at about 98 ℃;

the inner plate of the stepped micro-channel 23 is replaced and fixed in the cavity 13 and covered by a transparent glass cover plate 4, the transparent glass cover plate 4 is covered and pressed by an upper sealing cover plate 5 and is fixed on the base outer plate 1 by screws. The L-shaped cover plate 3 using the spacer plate 31 having a width of 2mm was attached to the experimental apparatus, and the heating power of the ceramic electric heater chip 6 was fixed and maintained so that the temperature of the chip was maintained at about 98 ℃, and the power supply to the ceramic electric heater chip 7 was cut off. The step section micro-channel 23 is six step section micro-channels with the same size and distributed at equal intervals. The depths of the front section and the rear section of the microchannel are different, the depth of the microchannel connected with the front section and the outer plate microchannel 12 is the same as that of the outer plate microchannel, the depth of the microchannel connected with the cavity 14 at the rear section is half of that of the front section, and the middle section of the microchannel is in a step shape as shown in a structure 231. Wherein the L-shaped cover plate 3 is used for adjusting the pressure of the working medium entering the microchannel, the ceramic electric heating plate 6 is used for preheating the working medium entering the experimental device, and the power of the ceramic electric heating plate 6 is controlled, so that the temperature of the preheated working medium is slightly lower than the saturation temperature of the saturated working medium by 100 ℃. After the pressure and preheating of the working medium has been set, the temperature and the pressure of the working medium are measured again in the measuring bore 17. The fluid working medium flows into the stepped microchannel 23 via the outer plate microchannel 12. When flowing in the step section microchannel 23, since the channel depths of the front and rear sections of the step section microchannel 23 are different, the channel sectional areas of the front and rear ends of the channel are different, the front end channel sectional area is large, and the rear end microchannel sectional area is small. When the fluid working medium flows from the front end with a larger cross-sectional area to the rear end, after passing through the structure 231, the pressure of the working medium in the channel changes suddenly due to the change of the cross-sectional area of the channel. It can be known from Bernoulli's law that the pressure on the fluid working medium flowing in the front-stage passage with a large cross-sectional area is large, and the pressure on the working medium flowing in the rear-stage passage with a small cross-sectional area is small. The saturation temperature of the liquid working medium will be lower as the pressure becomes lower. Since the temperature after the preheating treatment is close to the saturation temperature of the working medium by 100 ℃, the phenomenon of boiling two-phase flow can occur at the rear section of the step section microchannel 23 due to the reduction of the pressure of the working medium. The working medium flowing in the step section micro-channel 23 has the phenomenon that the front section part does not boil and the rear section part generates the boiling two-phase flow. The sensors at the first temperature pressure measuring hole 16, the second temperature pressure measuring hole 17 and the third temperature pressure measuring hole 18 in the experimental device measure the temperature and the pressure of the experimental working medium, a high-speed camera above the experimental device captures image information of a boiling two-phase flow phenomenon in the stepped micro-channel 23, and the acquired temperature pressure and image data are transmitted to a computer for further analysis.

Example 4

The inner plate of the spray pipe micro-channel 24 is used instead, the power supply of the ceramic electric heating sheet 7 is cut off, and the heating power of the ceramic electric heating sheet 6 is maintained to keep the temperature of the heating sheet at about 95 ℃;

the phenomenon of flash evaporation and boiling two-phase flow is induced, deionized water is used as a fluid working medium in an experiment, the experiment device is connected into the whole experiment loop, and normal-temperature deionized water flows into the rectangular channel inlet 11 through the experiment loop and enters the micro-channel experiment device. The inner plate of the micro-channel is replaced by an inner plate with a nozzle micro-channel 24, the inner plate is installed and fixed in the cavity 13, the upper surface of the inner plate is tightly attached to the transparent glass cover plate 4, and the transparent glass cover plate 4 is covered and pressed by the upper sealing cover plate 5 and is fixed on the outer plate 1 of the base through screws. The L-shaped cover plate 3 using the spacer plate 31 having a width of 2mm was mounted in the experimental apparatus, and the heating power of the ceramic electric heating sheet 6 was fixed and maintained so that the temperature of the heating sheet was maintained at about 95 deg.C, and the ceramic electric heating sheet 7 was not connected to a power supply. Wherein the ceramic electric heating plate 6 is used for preheating the working medium entering the experimental device, and the temperature of the preheated working medium is 100 ℃ lower than the saturation temperature of the preheated working medium. After preheating, the temperature and pressure of the fluid medium are measured again in the measuring holes 17 for a second time, and the fluid medium flows into the nozzle microchannel 24 via the outer plate microchannel 12. The nozzle microchannel 24 is six nozzle microchannels distributed at equal intervals, the front end of the microchannel is connected with the outer plate microchannel 12, the depth of the channel is the same, and the rear end of the microchannel is provided with a structure 241 for shielding the microchannel. Wherein the microchannel is partially covered in the structure 241, and only a small outlet is left in the middle, wherein the outlet is a round small outlet with the diameter of 0.5mm, and the function of the small spray pipe is similar to that of the small spray pipe. When the working medium flows into the buffer cavity 14 from the outlet of the structure 241, the working medium originally in the high-pressure environment of the micro-channel is forced to be released into the buffer cavity 14 lower than the self saturated vapor pressure through the fine nozzle of the structure 241 due to the excessively fine circular channel, the liquid in the buffer cavity 14 is violently vaporized due to the non-equilibrium overheat state, and the two-phase flow phenomenon is accompanied with explosive crushing atomization, namely flash atomization. The sensors at the first temperature pressure measuring hole 16, the second temperature pressure measuring hole 17 and the third temperature pressure measuring hole 18 measure the temperature and the pressure of the experimental working medium in the device, the high-speed camera above the experimental device captures the image information of the flash evaporation boiling two-phase flow phenomenon in the micro-channel 24, and the acquired temperature pressure and the image data are transmitted to the computer for further data analysis.

Example 5

Using the inner plates of the nozzle microchannel 24; the L-shaped cover plate 3 with the width of the isolation plate being 8mm is replaced, the power supply of the ceramic electric heating sheet 7 is cut off, and the heating power of the ceramic electric heating sheet 6 is maintained to keep the temperature of the heating sheet at about 95 ℃;

similarly to example 4, the inner plate of the nozzle microchannel 24 is still used, the inner plate is fixedly mounted in the cavity 13, the upper surface of the inner plate is tightly attached to the transparent glass cover plate 4, and the transparent glass cover plate 4 is covered and pressed by the upper sealing cover plate 5 and is fixed on the outer base plate 1 by screws. An L-shaped cover plate 3 having a width of 8mm was mounted in the experimental apparatus instead. The heating power of the ceramic electric heating sheet 6 is fixed and maintained to maintain the temperature of the heating sheet at about 95 ℃, and the power supply of the ceramic electric heating sheet 7 is cut off. Wherein the L-shaped cover plate 3 is used for adjusting the pressure of the working medium entering the microchannel, the ceramic electric heating plate 6 is used for preheating the working medium entering the experimental device, and the temperature of the preheated working medium is 100 ℃ lower than the saturation temperature of the preheated working medium. After the pressure and preheating of the working medium has been set, the temperature and the pressure of the working medium are measured again in the measuring bore 17. The fluid working medium flows through the outer plate microchannel 12 into the nozzle microchannel 24. Working fluid flows in nozzle microchannel 24 and out of the outlet of structure 241 into buffer chamber 14. After the pressure of the working medium in the microchannel is changed by using the L-shaped cover plate 4, the working medium in the microchannel 24 is released into the buffer cavity 14 which is lower than the self saturated vapor pressure through the fine nozzle of the structure 241, and the two-phase flow phenomenon of flash boiling still occurs. The severity of flash boiling in this example is lower than the flash boiling phenomenon of example four. The sensors at the second temperature pressure measuring hole 17 and the third temperature pressure measuring hole 18 measure the temperature and the pressure of the experimental working medium in the device, the high-speed camera above the experimental device captures the image information of the flash evaporation boiling two-phase flow phenomenon in the buffer cavity 14, and the acquired temperature pressure and image data are transmitted to the computer for further data analysis.

The above examples are two kinds of implementation manners of the present invention, but the implementation manners of the present invention can be further changed according to the actual requirements, and are not limited by the above examples, and any other changes, modifications, substitutions, combinations, simplifications which do not depart from the spirit and principle of the present invention should be regarded as equivalent replacement manners, and are included in the protection scope of the present invention.